The minimum amount of energy for a collision to be successful is called the activation energy. The rate of a reaction depends on the rate of successful collisions between reactant particles.

Activation energy is the minimum energy needed for ‘successful collisions’ where atoms within the reactants rearrange to form products. It can be represented on an energy level diagram.

Why is this not the case? In this case ultra violet radiation provides the energy to break bonds in the chlorine molecules. No third party reagent is used. If it were then it could be decribed as a ...